Optics can be thought of as performing mathematical operations transforming light intensities from different incident angles to locations on a two-dimensional image sensor. In the case of focusing optics, this transformation is the identity function: each angle is mapped to a distinct corresponding point on the sensor. When focusing optics are impractical due to size, cost, or material constraints, the right diffractive optic can perform an operation other than the identity function that is nonetheless useful to resolve image features of interest. In such cases the sensed data may bear little or no resemblance to the captured scene; however, a desired optical discrimination can still be resolved or computed from the sensor outputs.
Automated inspection often involves the visual determination of alignment of small parts or other visual tasks that require the accurate estimation of the position of a visual edge (e.g., a slit or bar). These applications may involve severe space constraints, especially if existing machines or devices are to be retro-fitted with such alignment estimators. Given these tight spatial constraints, the sensor should have wide angle-of-view. Low computational complexity, low cost, and ease of manufacturing of the sensor are desirable.